water heating temperature reduction for energy efficiency

You can reduce your water heating costs
by simply lowering the thermostat setting on your water heater. For each
10ºF reduction in water temperature, you can save between 3–5% in energy
costs.

Although some manufacturers set water heater thermostats at 140ºF, most
households usually only require them set at 120ºF or even 115ºF. Water heated
at 140ºF also poses a safety hazard – scalding. However, if you have
a dishwasher without a booster heater, it may require a water temperature
within a range of 130ºF to 140ºF for optimum cleaning.

Reducing your water temperature to 120ºF also slows mineral buildup and
corrosion in your water heater and pipes. This helps your water heater last
longer and operate at its maximum efficiency.

Consult your water heater owner's manual for instructions on how to operate
the thermostat. You can find a thermostat dial for a gas storage water heater
near the bottom of the tank on the gas valve. Electric water heaters, on
the other hand, may have thermostats positioned behind screw-on plates or
panels. As a safety precaution, shut off the electricity to the water heater
before removing/opening the panels. Keep in mind that an electric water
heater may have two thermostats – one each for the upper and lower
heating elements.

Mark the beginning temperature and the adjusted temperature on the thermostat
dial for future reference. After turning it down, check the water temperature
with a thermometer at the tap farthest from the water heater. Thermostat
dials are often inaccurate. Several adjustments may be necessary before
you get the right temperature.

If you plan to be away from home for at least 3 days, turn the thermostat
down to the lowest setting or completely turn off the water heater. To turn
off an electric water heater, switch off the circuit breaker to it. For
a gas water heater, make sure you know how to safely relight the pilot light
before turning it off.